Recurrent Lung Cancer Gene Found

For the first time, scientists have found a strong link between a specific genetic mutation and the prognosis of patients with a common type of cancer.

In studies of adenocarcinoma of the lung, the most prevalent form of lung cancer, researchers discovered that patients whose tumor cells contain the genetic mutation are far likelier to suffer a recurrence of cancer after surgery than patients who lack the mutation.

The mutation affects a tiny region of a vital gene known as K-ras, which is thought to help orchestrate tissue growth in the body. Once mutated, scientists believe, the gene becomes a potent agent of cancer.

The scientists said a probe fashioned from the mutant gene eventually may allow physicians to screen tumor cells and decide which of their adenocarcinoma patients require aggressive treatment even after surgical removal of the entire tumor.

``If a patient has adenocarcinoma of the lung with this mutation, it could be that the oncologist should consider additional therapy such as chemotherapy or radiation, even if the surgery seems to have been curative,`` said Dr. Sjoerd Rodenhuis of the Netherlands Cancer Institute in Amsterdam, an author of the new report, which appears in the current issue of The New England Journal of Medicine.

Lung cancer is the most common malignant cancer and the biggest cause of cancer death in the U.S., and adenocarcinomas account for 30 to 40 percent of all lung cancers. The American Cancer Society says about 157,000 people in the U.S. will come down with the malignancy in 1990, and 142,000 will die.

Doctors said that any type of lung cancer is an abysmal illness and the five-year survival rate is less than 10 percent. But if the tumor is detected before spreading to other organs and if its position in the lungs allows complete excision, the cure rate may be 40 to 80 percent, they said.

Doctors estimate that 1 in 4 adenocarcinomas can be removed surgically. Most patients whose adenocarcinomas are removed at an early stage do not receive further treatment.

Researchers said if the new results can be confirmed in a larger group of patients, the genetic mutation may be used to distinguish between those early- stage adenocarcinomas for which surgery spells an end to the disease and those that will recur and thus may merit more treatment.